With widely using of window-cleaning robots in household, whether the window-cleaning robot walks normally on the window will directly affect its window-cleaning result. The robot can walks normally only on the premise of skid resistance. FIG. 1 is a schematic figure of the structure of the elongated shape wiper of the window-cleaning robot according to the prior art. As shown in FIG. 1, a seat 200 of a window-cleaning robot 100 according to the prior art is provided with a drive wheel 300 and a suction cup 400. Typically, the seat 200 is also provided with an elongated silicone strip 500 used to wipe off water on the glass so as to prevent the drive wheel 300 from slipping due to contacting with the water and to prevent the suction cup 400 from getting wet by the water. Since the silicone strip according to the prior art is of an elongated shape structure, it can only effectively wipe off water in one direction (i.e., in the direction perpendicular to the direction along which the elongated shape structure is disposed), and if the window-cleaning robot revolves to the direction parallel to the direction along which the elongated structure is disposed, the robot cannot wipe off water and thus the drive wheel 300 may slip due to contacting with the water.